Advertising sign



Jgp 28,1938. R .H;'sE AMAN ET A 2.121.829

ADVERTISING SIIGN Filed Oct. 5, 1955 2 Sheets-Sheet l CarZA. Sciazezrdezz BY I g U 21110 RNEY Patented June 28, 1938 PATENT OFFICE ADVERTISING SIGN Richard H. Seaman, Los Angeles, and Carl A.

Schwenden, Alhambra, Calif., assignors, by direct and mesne assignments, of forty percent to said Seaman, forty percent to Walter T. Wells, Glendale, Calif., and twenty percent to. Lloyd Spencer, Los Angeles, Calif.

Application October 5, 1935, Serial No.- 43,'l42

Claims.

Our invention relates broadly to advertising signs and more particularly to an electrical circult arrangement and oscillating current source and means and methods for supplying oscillatory currents to electrical discharge tubes for producing predetermined electrical effects for use. in advertising signs.

One of the objects of our invention is to provide a system of mobile'electrical discharge in a sign which may be used, for instance, for adver-,

tising purposes in such a fashion that the mov- Ing glow discharge will either write words or trace drawings or both in any desired fashion.

Another object of our invention is to provide constructions of gas filled glow discharge tubes preformed in suitable shapes and connected to an electrical network which serves as exciter in such a way that the glow discharge can be varied in intensity as well' as made to move in any desired pattern.

Still another object of our invention is to proprovide a circuit arrangement for electrical devices adapted to eii'ect movement or progressive change in the glow discharge in an electrical.

discharge device.

Another object of our invention 'is to'provide a circuit arrangement for a plurality of glow discharge devices connected to a source of oscillating current for producing mobile discharges in the discharge devices.

Still another object of our invention is to provide a circuit arrangement of such character that for certain frequencies of the current of the source with respect to the natural frequency of an exciting coil connected across a glow tube system, a dark space can be made to move through the'glow discharge.

Other and further objects of our invention reside in the circuit arrangements and apparatus hereinafter more fully described with reference .to the accompanying drawings, in which:.

Figure 1 is a schematic diagram of one form of ourinvention, whereby a glow discharge can be made to move either from the left to the right,

towards the middle portion of the tube; Fig. 2 is a schematic diagram of a modification of our invention showing a twisted cable connecting the source to the exciting coil of the glow discharge device; Fig. 3 is another modification of our invention showing a Lecher wire feed; Fig. 4 illustrates a further modification of our invention employing a parallel wire feed; Fig. 5 is as'chematic diagram of our invention including a novel form of oscillator in connection with a glow discharge device whereby the desired discharge effects are efliciently produced; and Figs. 6 and '7 are schematic diagrams and illustrate schemes for operating several glow discharge devices in accordance with our invention.

Referring to the drawings in more detail, Fig. 1 shows a glow discharge device I which may be a wave-like tube of preformed shape, an ad vertising sign or the, like, having terminals 2 and 3 connected to an exciting coil 4. ,A connector 6 connects a suitable adjustable tap 5 'of the exciting, coil 4 to an adjustable tap l in the output circuit of an oscillator, shown in Fig. 1 as a pushpull electron tube oscillator, which produces an oscillatory current. It willbe observed that the connection between theoscillator and the exciting coil 4 is unipolar, the circuit being completed to the oscillator through the capacity of the tube I with respect to ground. The electron tubes 8 and 9 may be excited from an alternating current line In of the customary commercial frequency. Reference character ll denotes a filament heating transformer and I2, a plate supply transformer. In some cases, the secondaries of the filament heating transformer and the plate supply transformer can be associated with a common core and a common primary winding. In the arrangement shown in Fig. 1, where separate transformers are used, the plate voltage can be varied by means of a variometer [3, which may be a variable choke coil or a variable resistance.

This gives a means of changing the output power, for constant filament excitation. The terminals of the oscillator coil 14 are connected to plates l5 and I6, and grids l1 and I8 connect through condensers l9 and 20 to suitable adjustable taps 2| and 22 on the oscillator coil l4. Reference characters 23, 24, and 25 denote choke coils -with a fixed coil M to vary the output frequency.

The frequency can also be varied by means of an adjustable coil l4 as is well known in the art.

The operation of the system shown in Fig. 1 is as follows:

With the connector 6 connected to an adjustable tap 5 of exciter coil 4, such that the voltage between tap 5 and terminal 3 of the discharge device is larger than the voltage between tap 5 and terminal 2, a glow discharge will start from terminal 3 and progress along the wave-shaped tube I towards terminal 2; This operation can be made to repeat itself over and over if an intensity adjuster or an appropriate interrupter is employed. A variable filament resistancemay be manually or automatically varied in order to keep the glow discharge in constant motion from either end of the discharge device. This can also be done by moving adjustable tap 1 along coil I4. If the adjustable tap 5 is set to a position so that the voltage between tap 5 and terminal 2 is larger than that between tap 5 and terminal 3, the glow discharge will move from terminal 2 towards terminal 3.

Also, in the system shown in Fig. 1, if the frequency of the oscillator is changed from the value for resonance with the natural frequency of the exciting coil 4 and discharge tube I, a dark spot is produced in the glow discharge occurring in the tube I. This dark spot can be made to move from left to right, or right to left, by selectively changing the position of either tap 5 or tap l. The dark spot can also be produced by connection of a ground g at a suitable point of the exciter coil 4 as shown'in Fig. 1A.

It is also possible to produce a number of dark spots which can be made to move. If a number of points along the exciting coil 4 are grounded, substantially duplicating the connection to ground g shown in Fig. 1A, a dark spot will appear in the tube l in the relative position of each ground connection.

By the system of our invention, we are, therefore, able to make a glow discharge progressively form from one terminal to the other, or move a glow discharge, along tubes of any shape in any desired way. Hence, if tube I is, for instance, neon filled and bent into a form adapted for advertising, we can make the sign write or trace out a certain desired figure from one end of the ural frequency of the exciter coil, a dark region is produced somewhere in the glow of the tube l. The position of this dark region in the glow discharge is dependent upon the relative frequency between the frequency of the source and the natural frequency of the exciter coil, and is varied in the system of Fig. 1 by adjustment of the condenser 21 which afiects the frequency of the oscillator. We have, therefore, another means for producing motions in a glow discharge of a sign, which is useful in the art.

Fig. 2 shows another embodiment of the system of our invention. For clearness, the glow discharge tube I has a preformed wave-like shape,

and the terminals 2 and 3 of the discharge tube are connected to the exciter coil 4, as in Fig. 1.

A single tube 35 is connected into an oscillator though in most cases, it is more practical to operate the tube system from either a D. C. or an A. C.

' power supply system such as the standard lighting circuit. The plate 36 and the grid 31 connect to an oscillating circuit consisting of the coil i4 and the variable condenser 21. The condenser 34 and the resistor 26' are used to supply grid bias. The plate potential is applied through tap 39 on the oscillator coil l4.

A step-over resonator consisting of a coil 3|, another coil 32, and a variable condenser 33, serves the purpose of transferring an adjustable high frequency power from the tube oscillator to the glow discharge device. The magnitude of the power transferred can be adjusted by means of the coupling between coils 32 and I4, or between coils 3| and 30, or by means of both. -It can also very conveniently be done by placing a variable resistor in the link circuit 30--2829. For instance, in many of our experimental set-ups we use a motor driven variable resistance in this variable condenser 33. If the inductive coupling between the oscillator and the .link system 28 is sumciently loose, a pure sinusoidal current will flow along the link branch, if condenser 33 is set for resonance. Variation of the condenser from this position alters the Wave shape of the oscillations transferred and may be employed to produce dark sections in the glow discharge as hereinbefore described.

It will be noted that the link section 28 which is coupled to the step-over resonator through coil 30, consists of a twisted wire cable which will transfer maximum power from the step-over resonator 3|, 32, 33, to the exciter coil 4. The link system can also consist of a concentric tube feed for which the outside cylinder can be grounded and acts as one conductor while the axial wire which is shielded by the outside cylinder forms the other conductor. The coupling to the exciter coil 4 is effected by means of coupling coil 29 which can be moved along the exciter coil 4, in order to make the glow discharge move either from the left to theright or from the right to the left, as desired. Certain positions along the exciter coil 4 may be grounded as shown in Fig. 1A, which gives another means for modifying the glow discharge occurring in the tube l in the system of Fig. 2.

Fig. 3 illustrates a modification of the system of our invention shown in Fig. 2; For clearness, the

tubes or other forms of generating devices, are omitted and are considered as contained in the rectangle 45. Condenser 21 and coil l4 comprise the oscillating circuit, and the power is transferred inductively from coil l4 to coupling coil 44. Tuning is effected by means of condenser 43 connected in shunt to coupling coil 44 and controls the amount of power transferred to the discharge device. The link 42 represents a Lecher wire feed connecting to the coil 29 which is coupled at a selected position on the exciter coil 4, in order to produce a desired motion of the glow discharge pattern occurring in tube I. The operations are iubstagtially as set forth in connection with Figs.

.and

Fig. 4 shows another modification of our invention. Source 45 and coil l4 represent an oscillation generator connected through line 48 to the exciter coil 4 of the glow discharge device l. The coupling to the generator is made through condensers and 49 at suitable taps 5| and 52, and the connection to the exciter coil 4 is made through taps 41 and 46 at selected positions on the coil 4. The operations of the system are substantially as set forth in connection with the preceding figures, but in this case the adjustments are made by means of tap connections. Provisions are made for tuning the exciter system connected to the glow discharge device I to the generated frequency, as well as for changing the magnitude of the power transferred to the exciter coil 4.

Fig. 5 illustrates a preferred form of our invention comprising a novel oscillator circuit in combination with coupling means to the discharge device of the type shown in Fig. l, which, however, can be replaced by either of the arrangements shown in Figs. 1-4. For clarity, the oscillator circuit is shown employing a single three-element tube 63, having a filament cathode 64, a grid 65, and a plate 66. The grid is connected through a grid leak 62, shunted by a grid condenser 6| to a coil 54 which connects to one terminal of the filament cathode 64. The plate 66' is connected through a source of potential 58, shunted by condenser 84, to a coil 55 which connects to the same terminal of the filament cathode 64. The other terminal of the filament cathode 64 connects through a coil 56 to a variable resistor 60. A source of filament current 59 connects with the filament through plate coil 55 on the one hand and through the resistor 60 and filament coil 56 on the other hand. By-pass condenser 51 is connected in shunt with the source 59 and the resistor 60. The plate coil 55 and the filament coil 56 are wound bifilary and made exactly alike. Coils 54, 55 and 56 are arranged in inductive relation. The variable resistor 66 is adjusted either manually or automatically for varying the intensity of the oscillating power. The negative terminals of the plate and filament power supplies are preferably grounded.

Theoscillator circuit thus defined differs greatly from customary oscillators, since as far as dynamic potentials are concerned, the cathode is at a. comparatively high potential, and improved response in the output circuit to a variable cathode' current results. Connection from the oscillator is made by means of a tap 68 on the coil 55, or coil 54, as may be the case. Tuning condenser 21, connected in shunt with coils 54 and 55, affords a means for varying the frequency of the-oscillator. Tap 29 on the exciter coil 4 has the same function as explained in connection with Fig. 1, and the single wire feed 53 connects taps 68 and 29. In our research and development, we have found the system shown in Fig. -5 especially well adapted for producing mobile glow discharge patterns. We have shown the glow discharge tube 1 formed in a predetermined pattern such as the sign Flowlite. Any desired shape may be given to the sign.

Acombined system of feedingthe exciter coil may be employed using the connection 6 of Fig. 1, and arranging the exciter coil 4 in fixed inductive relation with coil I4 in the oscillator circuit, after the teaching in Figs. 2-4 of an inductively coupled link circuit.. In such a system, the inductive coupling provides for the transfer of energy to the exciter coil 4, and the position of connection 6 at tap 5 on the coil 4 determines the position of the standing waves in the coil 4 and the tube I.

Fig. 6 illustrates one method whereby several glow discharge tubes 59, 10, 1|, I2 are differently excited from the exciter coil 4 by means of suitable potentials produced at one end 4a, of

' have the same potentials impressed on the terminals thereof.

While we have described our invention in certain preferred embodiments, we desire it to be understood that various modifications may be made therein by those skilled in the art, and no limitations upon our invention are intended other than may be imposed by the scope of the appended claims.

What we claim as new and desire to secure by Letters Patent of the United States is as follows:

1. A glow discharge advertising sign connected across a coil which is energized by a unipolar connection at a suitable position on the coil from an oscillating source in such a way as to successively draw a predetermined pattern by means of a movable ionization glow, the circuit through said coil being completed through the capacity effect of the glow discharge sign with respect to ground.

2. A gaseous discharge a coil which is energized by means of a parallel wire link terminating at two suitable taps on said coil at one end and terminating at the other end at two suitable taps on a. coil carrying .an oscillating current for producing a mobile glow discharge pattern.

3. In an oscillating current generator, an exciter coil, a glow discharge device connected across said coil, and a link circuit coupled to said generator and said coil for transferring oscillating power to said coil for producing a movable glow discharge pattern.

4. An oscillating current source in combination with a plurality of cascade circuits, one of which constitutes a link for transferring oscillating power from said source to another of said circuits which applies the power to a discharge device producing a movable glow discharge pattern.

5. In a system for producing mobile glow discharges, an oscillator comprising an electron tube having a cathode, a grid, and a plate, circuits interconnecting said grid and said plate with one device connected across I terminal of said cathode and inductively coupled,

means connected with the other terminal of said cathode for maintaining said cathode at an elevated potential, variable means associated with said cathode for modifying the intensity of the output current of said oscillator; 'a glow discharge device, an exciter coil connected to the terminals of said discharge device, a connection from said oscillator circuit to a selected point on said exciter coil, the adjustment of said variable means controlling the speed of progression of the glow discharge in said device and the position of said selected point on the exciter coil determin ing the direction of the movement of the flow discharge. v

6. In a glow discharge system, means for producing a mobile glow discharge which comprise an oscillator arranged to produce a high frequency current varying in intensity in successive cycles, a discharge device, an exciter coil connected with said discharge device, and a connecting link circuit from said oscillator to said exciter coil adapted to determine the character of the movement of the mobile glow discharge produced by said varying high frequency current.

7. In a glow discharge system, means for producing a mobile glow discharge which comprise an oscillator arranged to produce a high frequency current varying in intensity in successive cycles, a discharge device, an exciter coil con nected with said discharge device, and a connecting link comprising a path through ground and a unipolar connection from said oscillator to a selected position on said exciter coil, the position of said connection determining the' character of the movement of .the mobile glow discharge produced by said varying high frequency current.

8. In a glow discharge system, means forproducing a mobile glow discharge which comprise an oscillator arranged to produce a high frequency current varying in intensity in successive cycles, a discharge device, an exciter coil connected with said discharge device, and a connecting link comprising a pair of connectors coupled with said oscillator and connected to selected positions on said exciter coil, the positions of said connections determining the character of themovement of the mobile glow discharge produced by said varying high frequency current.

9. In a glow discharge system, means for producing a mobile glow discharge which comprise a high frequency oscillator, a discharge device, an exciter coil connected with said discharge device, and a connecting link comprising a tunable circuit coupled with said oscillator, and a feed line terminating in a coupling coil arranged in inductive relation at a selected position on said exciter coil, the characteristics of said tunable circuit determining the character of the movement of the mobile glow discharge and the selected position of said coupling coil on said exciter coil determining the direction of movement of the glow discharge.

10. In a glow discharge system, means for producing a mobile glow discharge as set forth in which comprise an exciter coil connected with said source of current, and connections from said plurality of glow discharge tubes across different,

portions of said exciter coil,

12. In a glow discharge system, means for producing a mobile glow discharge as set forth in claim 9, and wherein said feed line comprises a Lecher wire feed.

13. In a glow discharge system, means for producing a progressive glow discharge in a predetermined direction which comprise a high frequency oscillator, a discharge device, an exciter coil connected with said discharge device, means for feeding energy from said oscillator'in a selected portion of said exciter coil, and means for varying the intensity of the energy from said oscillator, the glow discharge progressing with increase in said current in a direction determined by the position of said selected portion of the exciter coil.

14. In a glow discharge system, means for producing a glow discharge characterized by a mobile dark section, which comprise a high frequency oscillator, a discharge device, an exciter coil connected with said discharge device, a connection between said oscillator and said exciter coil, and a connection from ground to a selected point on said exciter coil intermediate the terminals of said coil.

15. In a glow discharge system, means -for producing a glow discharge characterized by a mobile dark section, which include an oscillating current source, a coil, a glow discharge device connected with said coil, and a link circuit interconnecting said coil and'said source.

RICHARD H. SEAMAN. CARL A. SCHWENDEN. 

